1. Technical Field
Tools for separating tires from wheels, and in particular, tools for forcing the separation of the bead portion of a tire from the bead-retaining portion of a wheel.
2. Description of Related Art
For well over a half century, tubeless pneumatic tires have been fitted directly to wheel rims, without the need for an inflatable inner tube that serves to contain pressurized air within the tire. FIGS. 1A and 1B schematically depict a typical pneumatic tubeless tire fitted to a wheel without the need for an inner tube. The wheel 10 is formed of a suitable structural material such as metal, composite, or high strength plastic, and is comprised of a mounting disk 12 and a rim section 15. The mounting disk 12 typically includes a center hole, and a plurality of holes arrayed on a bolt circle around the center hole for receiving wheel studs on a wheel hub (not shown). Other mounting disk arrangements for joining the wheel 10 to a wheel hub are well known and need not be described here.
The rim section 15 is comprised of a first rim member 20 and a second rim member 30. The first rim member 20 is comprised of a rim body 22, a bead seat 26, and a flange 28. The first rim member may also include a bead retainer 24. In like manner, the second rim member 30 is comprised of a rim body 32, a bead seat 36, a flange 38, and optionally, a bead retainer 34. The widths of the rim bodies 22 and 32 may differ, so as to provide an offset of the mounting disc 12 between the flanges 28 and 38, which provides additional space within the rim body 22 to accommodate brake drums, discs, calipers, and other vehicle components.
The tire 50 is comprised of a tread section 52, a first side wall 60, a first bead 62 containing a first bead bundle 64, and a second bead 72 containing a second bead bundle 74. (For the sake of simplicity of illustration, tread is not shown in tread section 52 in FIG. 1B.) When fitting the tire 50 to wheel 10, the first bead 62 and bead bundle 64 are sufficiently elastic so as to enable stretching of them (using tools) over flange 28 of wheel 10. In like manner, second bead 72 and bead bundle 74 are stretched over flange 38 of wheel 10. When compressed air is delivered into the tire 50 through a valve stem (not shown) fitted in wheel 10, the beads 62 and 72 are forced laterally outwardly along rim bodies 22 and 32, and “snap into position” over respective bead retainers 24 and 34. The beads 62 and 72 thus seat in sealing contact with bead seats 26 and 36. The bead bundles 64 and 74 are typically of a material that is less elastic than the rubber of the tire, such as steel wires, and are thus under high tension. This tension provides a tight seal of the tire beads 62 and 72 to the bead seats 26 and 36 of the wheel, thus obviating the need to use a tube within the tire, as was done prior to the 1960s.
This tension in the bead bundles 64 and 74, particularly in combination with the bead retention features 24 and 34, also makes it particularly difficult to unseat the tire beads from the bead seats, and remove the tire 50 from the wheel 10 when the need arises due to tread wear or puncturing of the tire. Modern tire changing equipment is effective for changing tires on typically sized car and truck wheels. However, such equipment is not capable of changing tires on rims which have pronounced bead retainers such as all-terrain vehicles (ATVs). Additionally, because of the stressful conditions in off-road use, ATV and other off-road wheels have particularly pronounced bead retention features that protrude from the rim bodies and serve to hold the tire bead in place in the event of loss of air pressure.
The need for changing ATV tires often arises “in the field,” away from a well-equipped tire store or vehicle service center that has expensive and complex pneumatic and hydraulic tools for changing a tire. Such tools are not available in remote locations where ATVs are used and may suddenly need tire service. Moreover, changing ATV/UTV tires is extremely difficult to do with existing hand operated tire changing tools available to the typical consumer. The bead retention features make changing the tire very difficult with conventional hand tools (such as hammers, pry bars, etc.), or existing hand operated tire changing tools, since the tire beads must be stretched over the retention features to remove the tire from the wheel. As a result, many “do-it yourself” (DIY) mechanics are forced to struggle with dangerous, damaging, and ineffective methods of breaking ATV tire beads, or they must resort to paying large service fees to get tires changed at dealerships or service stations.
Existing tire changing tools available for this task have flaws compared to an ideal solution. They do not work well on relatively small ATV wheels, and/or the tools are large and not portable, and/or they are complicated and difficult to use, and/or they cause damage to the wheels, and/or they are prohibitively expensive due to their complex construction.
Additionally, there is considerable variation in the dimensions of wheels and tires used on ATVs and other small vehicles. Referring again to FIG. 1B, the depths of the flanges 28 and 38 of the wheel 10 may vary widely among wheel manufacturers, and the shapes of the tire sidewalls 60 and 70 may also vary, depending on the width of the wheel 10 on which the tire 50 is mounted. In a tire changing tool, this variability must be accommodated. If the variability is not accommodated, I.e., if a “one size fits all” bead breaking tool is used on a wheel and tire of an incompatible size, damage to the wheel in the form of a gouge, crack, or other defect will likely result. The wheel may be rendered unusable, because it will not seal properly to a new tire.
Accordingly, there remains a need for a tire changing tool, which can separate the bead portion of a tire from the bead-retaining portion of a wheel, and which is simple, inexpensive, safe to use, portable, and effective across a range of tire and wheel geometries.